T and B lymphocyte function in patients with lupus nephritis: correlation with renal pathology.

The relationship between in vitro measures of T and B cell responses of peripheral blood lymphocytes and histological findings on renal biopsy was examined in 32 patients with lupus nephritis. T cell mediated responses, assessed by mixed leucocyte reaction (MLR) and cell mediated lympholysis (CML), were decreased, while spontaneous immunoglobulin secretion by B cells, measured by plaque forming cell (PFC) assay, was increased above normal in the whole patient population. There were no significant differences in these T or B cell responses between patients with the diffuse proliferative and the membranous forms of lupus nephritis. Using a semi-quantitative index of the histologic activity of diffuse proliferative lupus nephritis, a good correlation was noted between the degree of abnormality of B cell responses and the level of activity seen on renal biopsy. The nature of the relationship between B cell abnormalities and the expression of lupus nephritis warrants further study.